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# Other nasal problems: rhinolith, nasal myiasis, synechiae, antrochoanal polyp and CSF leak

- Topic

A one-sided blocked or smelly nose has a short list of causes: a stone, maggots, scar bands, a single polyp or leaking brain fluid.

Updated Nov 12, 2026

**See it in 3D:** [Nasal cavity](https://durgical.com/en/anatomy/nasal-cavity/) · [Nasal septum](https://durgical.com/en/anatomy/nasal-septum/) · [Inferior nasal conchae](https://durgical.com/en/anatomy/inferior-nasal-concha-bone/) · [Maxillary sinus](https://durgical.com/en/anatomy/maxillary-sinus/) · [Ethmoid bone](https://durgical.com/en/anatomy/ethmoid-bone/)

## Key points

- One-sided foul discharge: in a child, a foreign body; in an adult who had one as a child, think of a rhinolith.
- Nasal myiasis in the Americas is mostly caused by the New World screwworm (Cochliomyia hominivorax), whose larvae feed on living tissue.
- Risk for nasal myiasis: atrophic rhinitis, old ulcers (leishmaniasis, leprosy, cancer), poor hygiene, old age, disability and neglect.
- Antrochoanal polyp: single, one-sided, from the maxillary sinus to the choana, in teenagers and young adults; the sinus part must be removed or it recurs.
- Synechiae form where two raw mucosal surfaces touch (septum and turbinate) after surgery, cautery or packing.
- Clear, one-sided, watery discharge after trauma or surgery: test for beta-2 transferrin; a CSF leak carries a risk of meningitis.

## What it is

Most nasal blockage is two-sided and inflammatory. When it is one-sided, the list changes: a foreign body or the stone that forms around it (rhinolith), fly larvae in a neglected nose (nasal myiasis), scar bands after surgery or cautery (synechiae), a single polyp growing out of the maxillary sinus (antrochoanal polyp), a tumour, or clear fluid from the skull base (CSF leak). Each has a clue in the history and a typical look on nasal endoscopy. Nasal myiasis matters in rural Colombia: the New World screwworm lays its eggs at the nostril and its larvae eat living tissue, so it is an emergency. The approach to a runny nose and CSF leak is on its own page; here the focus is on recognising these problems and the next step.

## Structure

- Rhinolith: a calcified mass built around a nucleus, either exogenous (bead, seed, paper, cotton) or endogenous (blood clot, dried mucus).
- Nasal myiasis: infestation of the nasal cavity by fly larvae; in the Americas mainly Cochliomyia hominivorax, which can bore into the sinuses, orbit and skull base.
- Synechia: a band of scar tissue between the septum and the lateral wall, usually the inferior or middle turbinate.
- Antrochoanal polyp: a benign cystic polyp from the maxillary sinus mucosa that leaves through an ostium and grows backwards to the choana and nasopharynx (antral, nasal and choanal parts).
- CSF rhinorrhoea: a breach of the dura and bone of the skull base (cribriform plate, ethmoid or sphenoid roof); traumatic (including surgical) or spontaneous.

## Problems of the nasal cavity at a glance

| Problem | Typical patient | Key clue | Treatment |
| --- | --- | --- | --- |
| [Rhinolith](https://durgical.com/en/conditions/foreign-bodies-of-the-ear-and-nose/) | Adult or older child | Hard gritty mass, one-sided fetor | Endoscopic removal, sometimes in fragments |
| [Nasal myiasis](https://durgical.com/en/conditions/tungiasis-and-furuncular-myiasis/) | Neglected, elderly or disabled rural patient; atrophic or ulcerated nose | Live larvae, pain, bloody discharge, swelling | Admission, larvae removal, ivermectin, antibiotics if infected |
| Synechiae | After nasal surgery, cautery or packing | Scar band septum to turbinate | Division and a temporary septal splint |
| Antrochoanal polyp | Teenager or young adult | Single polyp reaching the choana | Endoscopic removal including its sinus part |
| [CSF leak](https://durgical.com/en/conditions/bacterial-meningitis/) | After head injury or skull base surgery, or spontaneous | Clear one-sided drip; beta-2 transferrin positive | Conservative care, then endoscopic repair |

## In clinical practice

- Rhinolith: slowly increasing one-sided blockage, foul (fetid) discharge, smell of rot, occasional bleeding; a hard, gritty grey mass on probing.
- Nasal myiasis: intense pain, itching or a crawling feeling, bloody foul discharge, swelling of the nose, face or eyelids, sneezing out larvae or seeing them move; it can destroy the septum, palate and orbit and reach the meninges.
- Synechiae: nasal blockage some weeks after surgery or cautery; seen as a band on rhinoscopy or endoscopy.
- Antrochoanal polyp: one-sided blockage, often worse on breathing out; the smooth grey mass may be seen behind the soft palate.
- A one-sided polyp or mass in an adult is not assumed benign: inverted papilloma and cancer must be excluded.
- CSF leak: clear, salty, one-sided drip that increases when leaning forward or straining; headache; recurrent meningitis is a warning that a leak exists.

## Next step / Initial management

- First workup of one-sided blockage or discharge: anterior rhinoscopy after decongestant and, by ENT, nasal endoscopy; sinus CT for rhinolith, polyp or suspected CSF leak.
- Nasal myiasis: refer the same day for admission; ENT removes the larvae (under endoscopy when deep), ivermectin is used as an adjunct, secondary infection is treated, CT shows the extent, and tetanus status is updated; look for the underlying cause and for neglect.
- Rhinolith and suspected foreign body: priority ENT referral for removal under good light and anaesthesia; never push the object backwards.
- Antrochoanal or any one-sided polyp: priority referral (within weeks) for endoscopy, CT and removal with histology.
- Suspected CSF leak: urgent referral to ENT or neurosurgery; collect the fluid for beta-2 transferrin, advise against nose blowing and straining, and teach the signs of meningitis.
- Synechiae causing blockage: routine ENT referral for division.

## Test yourself

Think of the answer, then tap the question to see it.

## A 78-year-old bedridden man from rural Colombia has severe nasal pain, bloody foul discharge and facial swelling; his carer saw worms in the nose. What is the diagnosis and the next step?

Nasal myiasis, most often by the New World screwworm. Same-day referral for admission, larvae removal, ivermectin as adjunct, antibiotics and CT for extent.

## A 16-year-old has one-sided nasal blockage. Endoscopy shows a single smooth grey polyp from the middle meatus reaching the nasopharynx. What is it?

An antrochoanal polyp, arising in the maxillary sinus; it is removed endoscopically together with its sinus part to prevent recurrence.

## A woman has had a one-sided foul nasal discharge for years. Probing touches a hard, gritty mass. What is the likely diagnosis?

A rhinolith: calcified material around a foreign body or clot; removed by ENT under endoscopy.

## Clear fluid drips from one nostril a week after a head injury. Which test confirms its origin?

Beta-2 transferrin in the fluid, which is specific for CSF; then imaging of the skull base and ENT or neurosurgical care.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/ent/other-nasal-problems-rhinolith-nasal-myiasis-synechiae-antrochoanal-polyp-and-cs/)

## Connections

## See it in 3D 5

The structures of Durgical's 3D anatomy where it is found.

- [Nasal cavity](https://durgical.com/en/anatomy/nasal-cavity/)
- [Nasal septum](https://durgical.com/en/anatomy/nasal-septum/)
- [Inferior nasal conchae](https://durgical.com/en/anatomy/inferior-nasal-concha-bone/)
- [Maxillary sinus](https://durgical.com/en/anatomy/maxillary-sinus/)
- [Ethmoid bone](https://durgical.com/en/anatomy/ethmoid-bone/)

## Related 5

- [Approach to a runny nose, including CSF leak](https://durgical.com/en/ent/approach-to-a-runny-nose-including-csf-leak/)
- [Approach to nasal blockage](https://durgical.com/en/ent/approach-to-nasal-blockage/)
- [Removing a foreign body from the ear or nose](https://durgical.com/en/ent/removing-a-foreign-body-from-the-ear-or-nose/)
- [Nasal exam: external nose, anterior rhinoscopy and nasal endoscopy](https://durgical.com/en/ent/nasal-exam-external-nose-anterior-rhinoscopy-and-nasal-endoscopy/)
- [Granulomatous diseases of the nose: leishmaniasis, leprosy, TB, syphilis, rhinoscleroma, rhinosporidiosis, GPA](https://durgical.com/en/ent/granulomatous-diseases-of-the-nose-leishmaniasis-leprosy-tb-syphilis-rhinosclero/)

## Related conditions 5

- [Foreign bodies of the ear and nose](https://durgical.com/en/conditions/foreign-bodies-of-the-ear-and-nose/)
- [Chronic rhinosinusitis and nasal polyps](https://durgical.com/en/conditions/chronic-rhinosinusitis-and-nasal-polyps/)
- [Tungiasis and furuncular myiasis](https://durgical.com/en/conditions/tungiasis-and-furuncular-myiasis/)
- [Bacterial meningitis](https://durgical.com/en/conditions/bacterial-meningitis/)
- [Sinonasal tumors](https://durgical.com/en/conditions/sinonasal-tumors/)

## Microorganisms 1

- [Dermatobia hominis](https://durgical.com/en/microbiology/dermatobia-hominis/)

## In Pharmacology 1

- [Ivermectin](https://durgical.com/en/pharmacology/ivermectin/)

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Educational content; it does not replace a medical assessment and is not a clinical instruction. For a real case, follow current guidelines and specialist advice.

Sources: [Nasal Foreign Body](https://www.ncbi.nlm.nih.gov/books/NBK459279/) (StatPearls Publishing (NCBI Bookshelf), 2023); [Myiasis (DPDx: Laboratory Identification of Parasites of Public Health Concern)](https://www.cdc.gov/dpdx/myiasis/index.html) (Centers for Disease Control and Prevention (CDC), 2024); [About Myiasis](https://www.cdc.gov/myiasis/about/index.html) (Centers for Disease Control and Prevention (CDC), 2024); [Nasal Polyps](https://www.ncbi.nlm.nih.gov/books/NBK560746/) (StatPearls Publishing (NCBI Bookshelf), 2025); [Cerebrospinal Fluid Leak](https://www.ncbi.nlm.nih.gov/books/NBK538157/) (StatPearls Publishing (NCBI Bookshelf), 2025).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/ent/other-nasal-problems-rhinolith-nasal-myiasis-synechiae-antrochoanal-polyp-and-cs/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/ent/other-nasal-problems-rhinolith-nasal-myiasis-synechiae-antrochoanal-polyp-and-cs/